Foam-tightened edge joint for structural panels

ABSTRACT

A joint for connecting two &#39;&#39;&#39;&#39;sandwich&#39;&#39;&#39;&#39; building elements. Each element has a locking rail on one end. The rails are in engagement with each other and have such form that they, when arranged, define one or more locking cavities. The more the rails overlap each other the larger is the cavity or cavities. In the cavity there is arranged an expanded foam body ensuring that the cavity will be as big as possible and will be filled up. This involves that the rails will overlap and cooperate efficiently so that the joint will be very tight.

United States Patent 1191 Bruun July 16, 1974 [54] FOAM-TIGHTENED EDGE JOINT FOR 3,357,742 12/1967 Furrer er a1 52 2 STRUCTURAL PANELS 3,381,420 5/ 1963 1 3,435,575 4/1969 [76] Inventor: Peer Bruun, Strandve en 151, 3060 533 13 97 ,Espergaerde, Denmark [22] Filed: Apr. 30, 1971 j y 3 gE ssistant xaminerayne e [21] Appl' 138363 Attorney, Agent, or Firm-Waters, Roditi, Schwartz &

Nissen [30] Foreign Application Priority Data May 17, 1970 Denmark 2213/70 [57] ABSTRACT A joint for connecting two sandwich building elei 52/758 ments. Each element has a locking rail on one end. The rails are in engagement with each other and have [58] ag 2 3 3 2 such form that they, when arranged, define one or 1 264/45 more locking cavities. The more the rails overlap each other the larger is the cavity or cavities. In the cavity there is arranged an expanded foam body ensuring [56] References cued that the cavity will be as big as possible and will be UNITED STATES PATENTS filled up. This involves that the rails will overlap and 1,925,417 9/1933 Swank..... 287/189.36 D X cooperate efficiently so that the joint will be very 2,266,702 12/1941 Byers 287/189.36 1) tight- I 2,644,553 7/1953 Cushman 287/l89.36 D 1 3,075,802 1/1963 Lowe 287/ 189.36 D X 1 Claim, 25 Drawing Figures II I I v 7 90a 7004 9a" 9a 1 80 PATENIEU JUL 1 5,1574

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The invention relates to a joint for connecting at least two structural parts such as building elements, for example plate-formed elements of the sandwich type.

It is known to manufacture such joints in which such end surfaces of the structural parts as are to be joined have cooperation recesses and projections and in which the parts are held together by means of a binding agent, or they are joined by nailing or by the insertion of a fixed or loose spring in recesses. The joints have a tendency to become leak in the course of a rather short time since it is not very suitable for absorbing shearing forces, and moisture will then be liable to seep through. In addition, the joint has a low heat insulating capacity.

It is the object of the invention to provide a joint of the aforesaid kind which in regard to heat insulation and strength becomes equal to the adjoining elements to a higher degree than hitherto known.

An essential feature of the joint according to the invention is that it embodies locking rails projecting from the end surface of each structural part and being in engagement behind each other, the locking rails being so formed as to define one or more locking cavities, the size of which up to a certain limit may be increased, the more the engagement area of the looking rails is increased, the said cavity containing an expandable body, preferably of adhesive foam material which, on reaching its maximum volume, presses parts of the locking rails into or against each other, simultaneously keeping the structural parts tightly joined. The locking rails form a closed locking cavity and when the cavity is filled by the expanding body, it will expand coincidental with the body. The invention also makes for a tight connection by way of the novel joint, for a good absorption of shearing forces in the structural parts, and for good heat insulating capacity.

According to the invention each locking rail is preferably embedded in a recess provided in the end surface of the individual structural part. As a result, the locking rails may be practically wholly concealed by the structural parts.

Various exemplary embodiments and modifications thereof are possible. Low weight is achieved by the invention joint, coupled with the earlier mentioned advantages. The embodiments are easily manufactured, and adapt themselves for a variety of requirements and applications.

The foam material is easily fed into the cavities of the invention joints. The cavities themselves are expanded as the foam expands, thereby strengthening the resulting structure. The force by which the structural parts are brought togehtercan be easily regulated.

The invention is also concerned with a method of manufacturing the aforesaid joints, and this method is characterized in that the locking rails of the two structural parts are brought into engagement behind each other, so as to form a locking cavity after which an expanding material, for example foam material, is introduced into the said cavity in order to expand the locking cavity and to cause the locking rails to be displaced in relation to each other, so that the said rails, and consequently the structural parts, are brought into their final interlocked position.

The invention will now be described with reference to the drawing, in which FIG. 1 shows two building elements of the sandwich type, provided with locking rails viewed in cross-section,

FIG. 2 is the same while a first embodiment of a joint according to the invention is being manufactured,

FIG. 3 the same after completion of the said joint,

FIG. 4 two plate-formed building elements of the sandwich type, provided with locking rails, which are of substantially the same width as the elements,

FIG. 5 the same after the locking rails having been passed into each other and the manufacture of another embodiment of the joint according to the invention having been commenced,

FIG. 6 the same after the manufacture of the said joint having been completed.

FIG. 7 two plate-formed building elements having different locking rails viewed in cross-section,

FIG. 8 the same after the locking rails having been joined and the manufacture of a third embodiment of the joint according to the invention having been commenced,

"FIG. 9 the same after the manufacture of the third embodiment of the assembly according to the invention having been completed,

FIG. 10 two building elements having locking rails constituted by plate sections projecting from and at right angles to the elements, and an auxiliary rail, the latter being just passed into position surrounding the projecting plate portions viewed in cross-section,

FIG. 11 the same, the auxiliary rail being passed into position so close to the elements as possible so that the manufacture of a fourth embodiment of the joint according to the invention may be commenced,

FIG. 12 the same, the manufacture of the joint disclosed in FIG. 11 being completed,

FIG. 13 two building elements provided with locking rails having a body of box-shaped profile, viewed in cross-section.

FIG. 14 is the same after the locking parts having been passed behind each other and the manufacture of a fifth embodiment of the joint according to the invention having been commenced.

FIG. 15 is the same after the joint shown in FIG. 14 having been completed.

FIG. 16 two building elements in which the locking rails are adapted by the outer plates of the elements being bentviewed in cross-section,

FIG. 17 is the same after the locking rails having been passed behind each other and the manufacture of a sixth embodiment of the joint according to the invention having been commenced,

FIG. 18 the joint shown in FIG. 17, after its completion,

FIG. 19 two building elements, in which each locking rail is provided by bending of both edge portions of the outer plate,

FIG. 20 the same after the locking rails having been passed behind each other and the manufacture of a seventh embodiment of the joint according to the invention having been commenced,

FIG. 21 the joint shown in FIG. 20, after its completion,

FIG. 22 a foam body from which all gases have been removed by suction and which is protected by a dense film, part of which, however, is cut away,

FIG. 23 the same, with the film pierced by a needle, so that the foam body-is wholly dilated by the film,

FIG. 24 the embodiment of the joint according to the invention shown in FIG. 3, the locking cavity being filled out by an inflatable body viewed in crosssection, and,

FIG. 25 a structural part mounted on a foundation by means of the joint according to the invention.

The structural parts 1 and 2 shown in FIG. 1 are formed as sandwich elements and consists of outer plates 3, 4, and 3a, 4a, respectively, and an intermediate filler such as a layer 5, 5a of foam material. At one end of the elements is provided an end piece 6, 6a with an end plate 7, 7a. In the said plate are formed recesses 8,'8a containing locking rails 9a and 10a of U-formed section. The rails have free side flanges 9a and 10a facing each other when the elements are to be joined. FIG. 2 shows the location of the locking rails in relation to each other after they have been brought into engagement behind each other. Free flanges 9a and 10a and parts of the bottom flanges 901" and 1011" define a locking cavity 15. The area in which the locking rails overlap each other, the so-called engagement area, is

provided with the reference character A. When the locking rails are in the position indicated in FIG. 2, expandable foam material 16 is filled into the locking cavity. 'As a result the side flanges 9a and 10a will be forced away from each other, by which the engagement area A is increased and the cavity is increased. During the final stage of joining the locking rails, the bottom flanges 901" and 10a will be guided by the adjacent recesses 8a and 8. When the locking rails have been fully joined, the cavity 15 will have the maximum volume 15 indicated in FIG. 3, and the foam material 16 will now constitute a very effective seal between the upper side and the underside of the elements. Auxiliary sealing lists 16, 17 and 16a, 17a may be embedded in special recesses provided in the end pieces 6 and 60 (FIG. I). When the elements have been joined, the lists 16 and 16a will rest in contact with each other, which also applies to the lists 17 and 17a. The foam material 16 may be introduced into the cavity 15 through holes (not shown) provided in one or both locking rails.

Whereas the locking rails 9a, 10a in FIGS. 11-33 are small, they are comparatively large in FIGS. 4-6 compared with the thickness of the building elements 1 and 2. In FIG. 4 the locking rails 93 and 10B are passed slightly into each other. Each locking rail consists of plate sections 19 and 20 of equal length projecting planely from the outer plates 3 and 4, in addition to a rail portion of U-formed crosssection attached between the said plates sections and having outwardly projecting edge sections 98"". The U-formed member has side flanges 9/3 and 9,8" and a bottom flange 913". In the building element 2 the locking rail 10 is composed of corresponding members 19a, 20a, 10B and 10B", 105' and 1013"". FIG. 4 shows the locking rails at the moment when the side flanges 9B and 10,8 are being introduced into cavities 21 and 22 of the neighboring rail.

FIG. 5 shows the locking rails after the flanges 9,8 and 1013 have been brought into engagement behind each other. They define a locking cavity 15, and when this is filled with an expandable foam material, the said material will force the flanges 9B and 10B away from each other and thus guide the locking rails into each other. When the rails have been joined halfway, the

plate section 20 of one rail will be brought to rest against the bottom flange 103' of the other rail and similarly the plate section 20a of the other rail will be brought to rest on the bottom flange 9/3" of the first mentioned rail. As a result, the rails will be guided very efficiently in relation to each other during the final stage in the expansion of the cavity 15. FIG. 6 shows the locking rails after they have been fully joined and the locking cavity 15 having obtained its maximum volume 15 as it is fully filled out by foam material 16.

FIG. 7 shows two building elements of the sandwich type, but each having only one outer layer 4a, 4 in addition to a foam layer 5, 5a. Near their ends the elements have end pieces 6, 6a. The locking rail 9y is of substantially U-formed section with side flanges 9y and 9y", a bottom flange 97 and an outwardly projecting edge flange 9'y"". The locking rail further comprises a plate section 20 which is an extension of the outer plate 4. One side of the edge flange 97" is attached at the plate section 20, whereas the other side and the outer side of the side flange 9y' is glued to the end piece 6. The other locking rail 107 of the locking element 2 if of L-formed section, in which the flanges are indicated by the reference characters 101 and 102. The flange 102 is attached to the outer plate 4a in such manner that the free distance between the flange 101 and the end piece 6a corresponds to the distance between the side flanges 97' and 9y" of the locking rail 9y. The distance between the side flange 101 and the extreme end 25 of the outer plate 4a corresponds to the width of the locking rail 9y less the width of the plate section 20. As a result the locking rails will (see FIG. 9) fit exactly together. FIG. 8 shows the locking rails at the stage in which the flange 101 has been passed in behind the flange 97' so as to form a locking cavity 15. As foam material is being injected into the said space, the flanges 9y and 101 will be forced away from each other, by which the locking rails are introduced into each other. FIG. 9 shows the locking cavity 15' at its maximum size, filled out with foam material 16. Also this joint is very tight and strong.

FIG. 10 shows further two building elements 1 and 2 composed of outer plates 3, 4, 3a, 4a and an intermediate layer 5, 5a and in which the outer plates 4, 4a are bent through to form locking rails and 108. Each locking rail consists of a flat flange. The outer plates 3 and 3a do not project as far as the outer plates 4, 40, by which they contribute to form locking recesses 26, 26a, and such recesses are also formed in the layers 5 and 5a. There is further provided an auxiliary rail 27 of substantially U-formed section and provided with outwardly directed edge flanges 27. When the elements are to be joined, the auxiliary rail 27 is caused to engage the rails 9 and 10, and is subsequently forced against the recesses 26 and 26a (FIG. 11). As a result, two locking cavities 15, will be formed and when an expanding foam material 16 is fed to the cavities, these will expand simultaneously with the locking rails 10y and 98 being passed towards each other, and the edge flanges 27"" are caused to fill out the recesses 26 and 26a completely (FIG. 12). The said Figure shows the locking cavities l5 and 150 in their maximum sizes (15 and 150). The locking rails of the building elements may also be of the design illustrated at 9e and 10s in FIG. 13. The rail 96, which is attached to the outer plates 3 and 4, consists of a box-shaped body 28 and two central flanges 29. The said flanges are attached to the body of two opposed flanges of the boxshaped section, which has a free flange 30. In the locking rail a the body has the reference character 280, the central flanges the reference characters 290 and the free flange the reference character 300. When the elements 1 and 2 are to be joined, the free flanges 30 and 300 are passed into position behind each other as indicated in FIG. 14. Since the bodies 28 and 280 are not of exact square shape, but formed so that they may be pushed into each other, cf. FIG. 15, a cavity formed between the flanges 30 and 300 may be increased by the action of foam material 16 (FIG. 15). FIG. 15 shows the locking cavity at its maximum size (15').

Locking rails 91;, 101 of very simple design are illustrated in FIG. 16. The locking rails are here formed as an extension of one end of one outer plate 3, 3a of each building element. The locking rails 91 and 101 are of L-section and their outwardly directed side flange 91 101; may be brought into engagement behind each other. The other flange 9n and 101;" of the L-sections is displaced towards the centre of the element by an amount corresponding to the thickness of an outer plate, and a shoulder 31, 32 is thus formed. When the flanges 101 91; have been brought into engagement behind each other as indicated in FIG. 17, and a cavity 15 thus formed is filled with expanded foam material 16, the flanges 911', 101 are forced away from each other. The locking cavity 15 will therebyobtain its maximum volume 15' by which the foamed material may provide an effective locking of the rails (FIG. 18). During the locking the free end of the outer plate 40 will side towards the shoulder 31 and the free end of the outer plate 4 will slide towards the shoulder 32.

A further development of the joint shown in FIGS. 16-18 is illustrated in FIGS. 19-21. One locking rail consists of a Z-formed plate section 9t lying in extension of the outer plate 3 and a plate section 9:." bent through 90 and connected with the plate 4. Similarly, another locking rail 10L is composed of a Z-formed plate section 10!. and a bent section 101.". FIG. 19 shows the two sandwich elements 1 and 2 in a position in which the locking rails are ready to be passed behind each other. FIG. 20 shows the elements after the Z- formed parts have been passed behind each other, thus forming a locking cavity 15. In FIG. 21 the said cavity has been filled with an expandable material 16, for example foam material, and this has now obtained its maximum volume 15'. The extreme ends of the Z- formed plate sections are introduced into the recess 35 and 36 (FIG. 19) of the filling layer of the elements so that the said elements are effectively locked and the assembly becomes tight.

Instead of injecting an expanding foam material into the cavity 15, one of the locking rails (this applies to all of the embodiments disclosed) may be provided with a foam body 160 which is surrounded by a thin air-tight film 161. The foam body is relieved of all gases, and so it is of a very small volume. The said body isillustrated in FIG. 22 with part of its end being removed. When the locking cavity is to be expanded, the film is punctured, which involves that the foam body will suck air and consequently expand. FIG. 23 shows the body in its full size. The foam body 160 is of a foam material with connected cells, for example polyurethane. The expanding foam material used in the joints according to FIGS. 1-18 is, however, a foam with non-connected introduced into the interior of the body. This embodiment of the invention has the advantage that the pres sure exerted by the body against the walls of the locking cavity is very easily regulated. Instead of an inflatable body use may be made of an elastic hollowbody, for example of neoprene. Before its insertion in the locking cavity 15 the cavity of the body is evacuated, but once the body has been inserted, it may be'punctured so that air enters. As a result the body will, owing to the elasticity, assume its normal form and fill out the locking cavity completely.

In the foregoing the invention has been described with reference to joining two building elements. However, there is nothing preventing also big structural parts from being joined by means of the joint according to the invention. Thus, FIG. 25 shows a wall element 1 mountedon a foundation 2. The said foundation is at its upper end surface provided with a locking rail 10, whereas the underside of the building element 1 has a non-visible locking rail. The element 1 and the foundation 2 are joined by expanding foam material injected into the non-visible locking cavity defined by the rails. The sealing between the elements will thus be very effective. The wall element 1 has furthermore a vertical locking rail which together with the locking rail 10 may cooperate with locking rails of the next locking element to be placed on the foundation 2.

The invention has in particular been found suitable for joining roof elements. However, the invention may be utilised in many other fields, for example for joining the wall elements of containers for transport. In addition, it may be used for joining wall elements in the walls of swimming pools, since it is a requirement of such walls that they are tight under all weather conditions. I

If use is made of expanding foam material which is unhardened while being fed into the cavity it is preferable to elect a foam material capable of producing a pressure of up to 10 kilpounds per centimeter squared during the expansion.

The building elements described in the foregoing may be manufactured in many ways, for example by extrusion. If desired, the outer plates 3, 4, 3a, 4a may be of metal, for example aluminium, or they may be of a metal having a thin plastic coating.

In regard to the attachment of the locking rails l and 2 to the building elements it'should be observed that, if necessary, they may be attached by means of an anchor projecting into the foam layer of the building elements.

The invention is not limited to "the embodiments de scribed in the foregoing, but may be modified in many ways without departing from its underlying idea.

I claim:

l. A joint for connecting at least two structural parts such as plate-formed building elements of the sandwich type, composed of two outer'plates and at least one intermediate filling layer such as a foam layer, the

7 joint comprising locking rails projecting from end surfaces of the building elements in pairs and being in engagement behind each other, webs of said rail pairs being at right angles to each other, said rails being of substantially U-formed section and turned about 180 in relation to each other, said rails defining at least one permanently closed locking cavity having solid angles of 90 at its corners, the size of said cavity being increased the more the engagement area of said rails is increased, and an expandable body of adhesive foam material in said cavity, which material, on reaching its maximum volume, presses parts of said rails at least partly into and at least partly against each other, simultaneously keeping the buidling elements tightly joined, and which foam material provides upon its expansion a tight connection between the building elements, said rails being embedded in recesses provided in said end surfaces of the respective building elements, said recesses in one building element having solid angles of at their comers and being large enough to receive parts of an adjacent one of said rails of another building element, wherein one side flange of said rails is attached in said recesses, and their free side flanges and bottom flanges cooperate to form said cavity, said rails include parts formed integral with at least one of said outer plates and parts attached thereto, and wherein a rail of one building element is a U-shaped sectional member, from one side flange of which projects an edge flange, the latter being attached to the edge of an outer plate of the corresponding building element, so that a part of said cavity of the sectional member is laid free, whereas a rail of another building element is an L-shaped sectional member, one flange of the latter being attached to an outer corresponding plate of the other building element.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 35 2 Dated Irjxventfofls) PeeT Bruun It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet item I30] "May 17', 1970" should read --May 1; 1970 Signed arid sealed this 19th day of November 1974.

(SEAL) Attest:

McCOYM. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-7 69 u.s. GOVERNMENT rnmfmo OFFICE: 86% 930 F ORM PO-1050 (10-69) 

1. A joint for connecting at least two structural parts such as plate-formed building elements of the ''''sandwich'''' type, composed of two outer plates and at least one intermediate filling layer such as a foam layer, the joint comprising locking rails projecting from end surfaces of the building elements in pairs and being in engagement behind each other, webs of said rail pairs being at right angles to each other, said rails being of substantially U-formed section and turned about 180* in relation to each other, said rails defining at least one permanently closed locking cavity having solid angles of 90* at its corners, the size of said cavity being increased the more the engagement area of said rails is increased, and an expandable body of adhesive foam material in said cavity, which material, on reaching its maximum volume, presses parts of said rails at least partly into and at least partly against each other, simultaneously keeping the buidling elements tightly joined, and which foam material provides upon its expansion a tight connection between the building elements, said rails being embedded in recesses provided in said end surfaces of the respective building elements, said recesses in one building element having solid angles of 90* at their corners and being large enough to receive parts of an adjacent one of said rails of another building element, wherein one side flange of said rails is attached in said recesses, and theiR free side flanges and bottom flanges cooperate to form said cavity, said rails include parts formed integral with at least one of said outer plates and parts attached thereto, and wherein a rail of one building element is a U-shaped sectional member, from one side flange of which projects an edge flange, the latter being attached to the edge of an outer plate of the corresponding building element, so that a part of said cavity of the sectional member is laid free, whereas a rail of another building element is an L-shaped sectional member, one flange of the latter being attached to an outer corresponding plate of the other building element. 